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  <title>Scale an image using the given new width and height</title>
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  <div id="layout-content"><div id="function.imagescale" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">imagescale</h1>
  <p class="verinfo">(PHP 5 &gt;= 5.5.0, PHP 7)</p><p class="refpurpose"><span class="refname">imagescale</span> &mdash; <span class="dc-title">Scale an image using the given new width and height</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.imagescale-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>imagescale</strong></span>
    ( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$image</code></span>
   , <span class="methodparam"><span class="type">int</span> <code class="parameter">$new_width</code></span>
   [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$new_height</code><span class="initializer"> = -1</span></span>
   [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$mode</code><span class="initializer"> = IMG_BILINEAR_FIXED</span></span>
  ]] ) : <span class="type">resource</span></div>

  <p class="para rdfs-comment">
   <span class="function"><strong>imagescale()</strong></span> scales an image using the given
   interpolation algorithm.
  </p>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <p class="para">
    Unlike many of other image functions, <span class="function"><strong>imagescale()</strong></span> does
    not modify the passed <code class="parameter">image</code>; instead, a
    <em class="emphasis">new</em> image is returned.
   </p>
  </p></blockquote>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.imagescale-parameters">
  <h3 class="title">参数</h3>
  <dl>

   <dt>
<code class="parameter">image</code></dt>

<dd>
<p class="para">由图象创建函数(例如<span class="function"><a href="imagecreatetruecolor.html" class="function">imagecreatetruecolor()</a></span>)返回的图象资源。</p></dd>

   
    <dt>
<code class="parameter">new_width</code></dt>

    <dd>

     <p class="para">
      The width to scale the image to.
     </p>
    </dd>

   
   
    <dt>
<code class="parameter">new_height</code></dt>

    <dd>

     <p class="para">
      The height to scale the image to. If omitted or negative, the aspect
      ratio will be preserved.
     </p>
     <div class="caution"><strong class="caution">Caution</strong>
      <p class="para">
       You should always provide the height if using PHP 5.5.18 or earlier, or
       PHP 5.6.2 or earlier, as the aspect ratio calculation was incorrect.
      </p>
     </div>
    </dd>

   
   
    <dt>
<code class="parameter">mode</code></dt>

    <dd>

     <p class="para">
      One of <strong><code>IMG_NEAREST_NEIGHBOUR</code></strong>,
      <strong><code>IMG_BILINEAR_FIXED</code></strong>,
      <strong><code>IMG_BICUBIC</code></strong>,
      <strong><code>IMG_BICUBIC_FIXED</code></strong> or anything else (will use two
      pass).
      <blockquote class="note"><p><strong class="note">Note</strong>: 
       <span class="simpara">
        <strong><code>IMG_WEIGHTED4</code></strong> is not yet supported.
       </span>
      </p></blockquote>
     </p>
    </dd>

   
  </dl>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.imagescale-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Return the scaled image resource on success 或者在失败时返回 <strong><code>FALSE</code></strong>.
  </p>
 </div>


 <div class="refsect1 changelog" id="refsect1-function.imagescale-changelog">
  <h3 class="title">更新日志</h3>
  <p class="para">
   <table class="doctable informaltable">
    
     <thead>
      <tr>
       <th>版本</th>
       <th>说明</th>
      </tr>

     </thead>

     <tbody class="tbody">
      <tr>
       <td>5.5.19/5.6.3</td>
       <td>
        The calculation of the height if <code class="parameter">new_height</code> was
        negative or omitted was fixed; prior to these versions, the aspect
        ratio was not maintained correctly.
       </td>
      </tr>

     </tbody>
    
   </table>

  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.imagescale-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <span class="function"><a href="imagecopyresized.html" class="function" rel="rdfs-seeAlso">imagecopyresized()</a> - 拷贝部分图像并调整大小</span>
   <span class="function"><a href="imagecopyresampled.html" class="function" rel="rdfs-seeAlso">imagecopyresampled()</a> - 重采样拷贝部分图像并调整大小</span>
  </p>
 </div>


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